U.S. Secretary of State Hillary Rodham Clinton accused Syrian President Bashar Assad of doubling down on "simply unconscionable" violence on Thursday, a day after reports that at least 78 people—including women and children—were killed by pro-government forces near Hama.

Monitors from the United Nations were trying Thursday to reach the village to verify the latest massacre, according to Reuters. As many as 40 women and children were among the 78 killed in Mazraat al-Qubeir, near Hama, on Wednesday, opposition activists said.

"We're disgusted by what we see happening," Clinton said in Istanbul, where she was scheduled to meet with envoys from 16 European, Turkish and Arab countries. "The regime-sponsored violence that we witnessed again in Hama yesterday is simply unconscionable. Assad has doubled down on his brutality and duplicity, and Syria will not, cannot be peaceful, stable or certainly democratic until Assad goes."

Clinton's comments came as the White House attempts to sharpen its tone on Assad's four-decade regime, and unite allies in putting pressure on the Syrian leader.

"We have to do more to help organize and focus the opposition," she said.

The Syrian government denied responsibility, blaming terrorists for the latest spate of killings. But U.N. confirmation, Reuters noted, would "pile pressure" on world leaders "who have been paralyzed by rifts pitting Western and most Arab states against Assad's defenders in Russia, China and Iran."

"Truthfully, not even monsters would carry out [the crimes] that we have seen, especially the Houla massacre," Assad said in a televised speech to the Syrian parliament in Damascus. "There are no Arabic or even human words to describe it. The criminal or criminals who committed this crime and others are not criminals for an hour or criminals for a day, they are constant criminals and are surely planning other crimes."